1. Field of the Invention
The present invention relates to a grip tip of a gripper for a parts having a different shape in a surface mount device, and in particular to an improved grip tip which can be easily attached/detached to/from a gripper for picking up a parts having a different shape, transferring the parts to a printed circuit board, and mounting the parts on the printed circuit board, and which can firmly support the parts, when a surface mount device mounts the parts on the printed circuit board.
2. Description of the Background Art
A surface mount device is used to rapidly precisely mount a plurality of parts on a printed circuit board. A structure of the surface mount device for rapidly precisely mounting parts on the printed circuit board will now be explained with reference to the accompanying drawings. FIG. 1 is a plan view illustrating the surface mount device. As shown therein, the surface mount device 10 includes an X-Y gantry 11, a printed circuit board conveyor 12, a module head 13 and a nozzle exchanging apparatus 14.
The X-Y gantry 11 transfers the module head 13 in an X-Y axis direction. The module head 13 transferred by the X-Y gantry 11 in the X-Y axis direction transfers a parts to a printed circuit board 1. The printed circuit board 1 is transferred to a mounting operation position A by the printed circuit board conveyor 12. When the printed circuit board 1 is transferred to the mounting operation position A by the printed circuit board conveyor 12, the module head 13 sucks the parts, transfers the parts to the printed circuit board 1, and mounts the parts on the printed circuit board 1.
The module head 13 sucking the parts and transferring the sucked parts to the printed circuit board 1 includes a plurality of nozzle devices 20. A structure of the nozzle device 20 will now be explained with reference to FIG. 2. Referring to FIG. 2, the nozzle device 20 includes a socket unit 21 and a holder unit 22. The socket unit 21 includes a hollow shaft 21a, an assembly block 21b, a connection block 21c, a socket shaft 21d and an elastic member 21e. The holder unit 22 includes a holder 22a and a holder shaft 22b. 
The hollow shaft 21a of the socket unit 21 has a hollow, and the connection block 21c is installed by the assembly block 21b on the bottom surface of the hollow shaft 21a. The holder 22a of the holder unit 22 is provided in the connection block 21c installed by the assembly block 21b. The socket shaft 21d and the elastic member 21c are disposed at the bottom surface of the connection block 21c in order to firmly and detachably support the holder 22a installed in the connection block 21c. 
The socket shaft 21d of the connection block 21c is supported at both side portions of the connection block 21c by the elastic member 21e. The socket shaft 21d installed at both side portions of the connection block 21c by the elastic member 21e supports both side portions of the holder 22a of the holder unit 22 in installation. The holder shaft 22b is formed on the bottom surface of the holder 22a having its side portions supported by the socket shaft 21d. 
When the holder 22a is installed in the connection block 21c, a nozzle (not shown) is mounted on the holder shaft 22b. In this state, a component is sucked by he nozzle, transferred to the printed circuit board 1, and mounted thereon. To replace the holder unit 22, the socket unit 21 is moved to a nozzle exchanging apparatus (14 in FIG. 1), and rapidly moved in a vertical direction to pick up the holder unit 22, thereby mounting and replacing the holder unit 22. The nozzle (not shown) is mounted inside of the holder shaft 22b of the replaced holder unit 22.
The nozzle is formed to pick up a surface mounting parts having a constant shape and size and to mount the parts on the printed circuit board. Accordingly, a gripper is used to pick up a parts having a different shape and size. However, the conventional gripper does not firmly pick up the parts having the different shape and size, and is not easily attached or detached.
Accordingly, it is a primary object of the present invention to provide a grip tip which can firmly support a parts having a different shape and which can be easily attached/detached to/from a gripper for the parts having the different shape in a surface mount device, when the gripper mounts the parts on a printed circuit board.
Another object of the present invention is to provide a grip tip which can firmly pick up a parts having a different shape, easily mount the parts on a printed circuit board, and be easily attached/detached to/from a gripper.
In order to achieve the above-described objects of the invention, there is provided, in a surface mount device including a holder mounted in a socket unit to be adhered closely to a socket shaft by an elastic force of an elastic body connected to the socket shaft, a grip tip of a gripper for a parts having a different shape adapted to the surface mount device comprising: a piston installed inside of a through hole formed at the holder, and lifted or lowered by air flown in/out through the through hole; a moving unit adjacently positioned to an inner slanted surface of a slanted member formed on the bottom surface of the piston, and connected to fixed blocks of the holder by a connection means for increasing or decreasing an interval according to the lifting or lowering operation of the piston; and a plurality of grip tips provided to moving blocks of the moving unit through a fixed member, for supporting at least three points of a parts having a different shape.